Mike'sHorseBarn 2,998 #1 Posted March 9, 2023 (edited) Is there a way to test a rectifier and see if it's bad? I'd like to test that before I just throw a new one on. I'd like to diagnose if it's that or if the problem is under the flywheel. Edited March 9, 2023 by Mike'sHorseBarn Share this post Link to post Share on other sites
ebinmaine 67,462 #2 Posted March 9, 2023 If you have a dvom or volt meter you can test the output of the engine to see what the voltage is there. Should be 35, 38 volts AC. 1 1 Share this post Link to post Share on other sites
Handy Don 12,217 #3 Posted March 9, 2023 (edited) To the question of testing a rectifier, yes that would be doable. But most WH engines use a voltage regulator, not a rectifier. Standalone testing of these requires more equipment than a volt meter. The voltage regulator has two jobs: convert the variable voltage A/C power coming from the stator on the engine into DC power, and to regulate the amount of voltage and current flowing through to the battery so it can charge safely. As @ebinmaine notes, it can be “yes or no” tested on a running engine assuming the other parts of the electrical system (stator, battery, wiring) are working properly. Assuming the battery is in good condition and reads ~12v with the engine off Then with the engine running well above idle, if: - the stator is generating up to 35 or so volts A/C on its two wires both when connected and when not connected to the regulator - and the regulator is well grounded - and the wiring connections are good - and the regulator's output is between 13 and 16 volts to the battery with the stator wires connected and the battery wire connected, then “probably it’s ok”. Edited March 9, 2023 by Handy Don 3 1 1 Share this post Link to post Share on other sites
Mike'sHorseBarn 2,998 #4 Posted March 9, 2023 2 hours ago, Handy Don said: To the question of testing a rectifier, yes that would be doable. But most WH engines use a voltage regulator, not a rectifier. Standalone testing of these requires more equipment than a volt meter. The voltage regulator has two jobs: convert the variable voltage A/C power coming from the stator on the engine into DC power, and to regulate the amount of voltage and current flowing through to the battery so it can charge safely. As @ebinmaine notes, it can be “yes or no” tested on a running engine assuming the other parts of the electrical system (stator, battery, wiring) are working properly. Assuming the battery is in good condition and reads ~12v with the engine off Then with the engine running well above idle, if: - the stator is generating up to 35 or so volts A/C on its two wires both when connected and when not connected to the regulator - and the regulator is well grounded - and the wiring connections are good - and the regulator's output is between 13 and 16 volts to the battery with the stator wires connected and the battery wire connected, then “probably it’s ok”. I'll give this a try. Thanks! 1 Share this post Link to post Share on other sites
Blasterdad 2,692 #5 Posted March 11, 2023 (edited) On 3/8/2023 at 10:03 PM, Mike'sHorseBarn said: most WH engines use a voltage regulator, not a rectifier. Standalone testing of these requires more equipment than a volt meter. The voltage regulator has two jobs: convert the variable voltage A/C power coming from the stator on the engine into DC power, and to regulate the amount of voltage and current flowing through to the battery so it can charge safely. Not true, the rectifier converts the AC voltage to DC, then the regulator controlls the output DC voltage & prevents overcharging. A regulator does not convert AC to DC voltage. Just a voltage regulator was used on the older Kohler engines with the belt driven generator/starter combination. Regulator/rectifier Regulator Edited March 11, 2023 by Blasterdad Share this post Link to post Share on other sites
